Activity of the Pt/WO 4 2− /ZrO2 catalyst in hydroisomerization reaction of n-heptane-benzene mixture

Kuznetsova, L. N.; Kazbanova, A. V.; Kuznetsov, Petr; Tarasova, L. S.

doi:10.1134/s0965544115010090

Cited by 9 publications

(10 citation statements)

References 16 publications

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“…Figure 29 reveals the presence of two temperature regions of CO 2 evolution, i.e., from 250 to 260 °C and above 300 °C. 88 The latter region was influenced by experimental temperature. This was evident by the shift of the CO 2 peak to higher temperature confirming a higher refractory structure of coke formed at higher temperatures.…”

Section: Energy and Fuelsmentioning

confidence: 99%

“…Similarly, the bimetallic Pt-Pd(3:1)/ WO 3 -ZrO 2 catalyst was more stable and resistant to sulfur poisoning and coke formation than monometallic Pt/WO 3 -ZrO 2 catalyst. 79 Kuznetsova et al 88 used the Pt/WO 3 -ZrO 2 catalyst for the HIS of n-heptane alone and in the mixture with benzene. The experiments were conducted in a continuous system near atmospheric pressure of H 2 between 200 and 280 °C.…”

Section: Energy and Fuelsmentioning

confidence: 99%

See 1 more Smart Citation

Hydroprocessing Catalysts Containing Noble Metals: Deactivation, Regeneration, Metals Reclamation, and Environment and Safety

Marafi

Furimsky²

2017

Energy Fuels

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Interest in the use of catalysts containing noble metals (NMs) in various hydroprocessing (HPR) applications is the result of an increasing volume of unconventional feeds and a continuous change in performance parameters of petroleum products. Conventional HPR catalysts can only partially fulfill new requirements. The high price of NMs and their high activity under both reducing and oxidative atmospheres require some modifications of the strategies that have been used for the handling of spent conventional HPR catalysts. Because of their higher activity, the deactivation of NMs-containing catalysts during HPR occurs under less severe conditions compared with that of conventional HPR catalysts. However, adverse effects of sulfur, nitrogen, oxygenates, and metals in feeds may require a higher severity to achieve HPR objectives. The activity of spent NMscontaining catalysts can be almost completely recovered by regeneration. The oxidative regeneration of spent NMs-containing catalysts has been performed commercially, while reductive and extractive regenerations offer alternative routes. The high value of NMs dictates that metal recovery is the only option if an adequate catalyst activity recovery cannot be achieved by regeneration. The methods are available for NMs recovery on an industrial scale. Also, the research aiming at improvement of metals recovery via existing methods as well as development novel methods has been noted.

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Section: Energy and Fuelsmentioning

confidence: 99%

Section: Energy and Fuelsmentioning

confidence: 99%

Hydroprocessing Catalysts Containing Noble Metals: Deactivation, Regeneration, Metals Reclamation, and Environment and Safety

Marafi

Furimsky²

2017

Energy Fuels

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“…Zbuzek et al analyzed the coke on a hydrodesulfurization catalyst with Raman spectroscopy and showed an E 2g 2 peak of graphite at 1580–1600 cm –1 with intensity equal to that of the peak at 1350 cm –1 , indicating the presence of graphite-like structure in the coke although the graphitic character is weak. Some researchers studied the coke on hydrogenation catalysts by temperature-programmed oxidation (TPO) − and showed that most of the coke could only be oxidized at temperatures higher than 500 °C, except in a few cases where about 20% coke formed on an industrial diesel hydrogenation catalyst can be oxidized at temperatures below 500 °C . Since the H/C molar ratio of more than 1 contradicts the graphite-like structure, it seems possible that the coke formed on hydrogenation catalysts distributes in different forms, i.e., some of them are more condensed with less hydrogen, whereas some others are relatively less condensed with more hydrogen, which is reasonable considering the catalyst surface is heterogeneous and consists of at least active sites and support.…”

Section: Introductionmentioning

confidence: 99%

Coke Removal from a Deactivated Industrial Diesel Hydrogenation Catalyst by Tetralin at 300–400 °C

Shi

Liu

et al. 2019

Energy Fuels

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Coke deposition on hydrotreating catalysts is one of the main reasons of deactivation. In situ coke removal is advantageous compared to the off-site coke removal. This paper studies tetralin (THN) treatment of a deactivated industrial diesel hydrogenation Mo−Co−Ni/W−Al catalyst at conditions similar to the operation, 300−400 °C without H 2 . The results show that the coke on the Mo sulfide sites, corresponding to 19−23% total coke, can be removed in 3 min to fully restore the catalyst's activity. The coke on the support cannot be removed. On the basis of the temperature-programmed oxidation, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and electron spin resonance, coke removal mechanism is discussed, which includes activation of H radicals in THN by the Mo sulfide sites and hydrogenation of coke by the H radicals. The minimal requirement for the coke removal is 340 °C for 3 min. The side reactions of THN are significant at higher temperatures and longer treatment times. The radical concentration of coke on the Mo sulfide sites is similar to that of lignites and is approximately 10 times the coke on the catalyst support.

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“…SO 4 2− /ZrO 2 catalysts have attracted significant attention because of their ability to isomerize light alkanes at low temperature, but suffer from the disadvantages of deactivation and possibly from sulfur loss during reaction and regeneration, limiting their applicability in isomerization. As an alternative to SO 4 2− /ZrO 2 , WO 3 /ZrO 2 has become increasingly important since its discovery by WO3/ZrO2 type catalyst shows high selectivity in the isomerization reaction of linear alkane, the catalyst activity is relatively low and the degree of cracking is too high [8]. Thus, the catalyst needs to be modified to meet the industrial production requirements.…”

Section: Introductionmentioning

confidence: 99%

“…In addition, the study on the stability of Cr-Pt/WO 3 /ZrO 2 indicates that the catalyst is not deactivated after 500 h of the n-heptane isomerization reaction.Arata and Hino [6] because of its good stability both in reducing and oxidizing conditions [7]. While the WO 3 /ZrO 2 type catalyst shows high selectivity in the isomerization reaction of linear alkane, the catalyst activity is relatively low and the degree of cracking is too high [8]. Thus, the catalyst needs to be modified to meet the industrial production requirements.…”

mentioning

confidence: 99%

Effect of the Cr2O3 Promoter on Pt/WO3-ZrO2 Catalysts for n-Heptane Isomerization

Zhang

Zhao

et al. 2018

Catalysts

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Isomerate, the product of a light naphtha Isomerization unit, is a clean, high-octane gasoline blending component, which is free of sulfur content, aromatics, and olefins. However, the isomerization of the long-chain alkanes, such as n-heptane, is pretty difficult. As a result, this process has not been commercialized yet. In recent years, much attention has been paid to Pt/WO 3 /ZrO 2 as an n-heptane isomerization catalyst due to its good thermal stability, strong acidity, simplicity of preparation, reusability and good isomerization activity. In this work, the Pt/WO 3 /ZrO 2 catalyst was modified by various loading of metal Cr to improve the catalytic performance. The effects of WO 3 content, Cr metal loading and calcination temperature on the catalyst characters and catalytic activity were studied. It is shown that Cr-Pt/WO 3 /ZrO 2 with the loading of 18 wt% WO 3 and 1.0-1.4 wt% Cr, prepared at the calcination temperature of 800 • C, has the highest activity. It was found that the octane number increases by 28 units through the isomerization of light naphtha feedstocks. In addition, the study on the stability of Cr-Pt/WO 3 /ZrO 2 indicates that the catalyst is not deactivated after 500 h of the n-heptane isomerization reaction.Arata and Hino [6] because of its good stability both in reducing and oxidizing conditions [7]. While the WO 3 /ZrO 2 type catalyst shows high selectivity in the isomerization reaction of linear alkane, the catalyst activity is relatively low and the degree of cracking is too high [8]. Thus, the catalyst needs to be modified to meet the industrial production requirements. The catalyst consisting of Pt deposited on WO 3 /ZrO 2 for n-heptane isomerization has attracted the attention of a large number of researchers as the most promising catalyst [9,10]. The structure of the WO 3 /ZrO 2 catalyst varies depending on the WO 3 content [11,12], leading to different catalyst activities. The structure and properties of this kind of catalyst can be modified by changing the WO 3 content [13]. While most researchers believe that the best catalytic activity is obtained when WO 3 is highly dispersed on the surface of the catalyst, there has been some debate about this subject. It was shown that the catalyst has better catalyst activity with the WO 3 density of seven-eight atoms·nm −2 [14,15]. Many researchers have found that the addition of small amounts of metals such as Fe, Al, In, and Ga to Pt/WO 3 /ZrO 2 enhances catalysis and stability of n-heptane isomerization, and it was demonstrated that Cr can be used as a modifier in Pt/WO 3 /ZrO 2 catalysts. Based on economic considerations, Cr metal is a more cost-effective option, and is therefore a more suitable for industrial production than Ga metal [16][17][18]. In this work, n-heptane isomerization over Cr-promoted Pt/WO 3 /ZrO 2 was studied and compared to that over Pt/WO 3 /ZrO 2 . Results and Discussion Effect of Cr 2 O 3 Loading on Pt/ WO 3 /ZrO 2 Characterization of the CatalystsThe XRD patterns of Cr-Pt/WZ catalysts with different Cr loading ...

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Activity of the Pt/WO 4 2− /ZrO2 catalyst in hydroisomerization reaction of n-heptane-benzene mixture

Cited by 9 publications

References 16 publications

Hydroprocessing Catalysts Containing Noble Metals: Deactivation, Regeneration, Metals Reclamation, and Environment and Safety

Hydroprocessing Catalysts Containing Noble Metals: Deactivation, Regeneration, Metals Reclamation, and Environment and Safety

Coke Removal from a Deactivated Industrial Diesel Hydrogenation Catalyst by Tetralin at 300–400 °C

Effect of the Cr2O3 Promoter on Pt/WO3-ZrO2 Catalysts for n-Heptane Isomerization

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